MAGNESIUM: 4 funnels of 108 atoms
Atomic weight 24.18
Number weight 432/18 24.00
ZINC (Plate IX, 2) also brings a new device: the funnel is of the same type as that of magnesium, while septets are substituted for the triplets, and 36 additional atoms are thus slipped in. Then we see four spikes, alternating with the funnels and pointing to the angles, each adding 144 atoms to the total. The spikes show the ten-atomed triangle, already met with in other metals, three very regular pillars, each with six spheres, containing two, three, four, four, three, two atoms, respectively. The supporting spheres are on the model of the central globe, but contain more atoms. Funnels and spikes alike radiate from a simple central globe, in which five contained spheres are arranged crosswise, preparing for the fully developed cross of cadmium. The ends of the cross touch the bottoms of the funnels.
ZINC: 4 funnels of 144 atoms 576
4 spikes of 144 atoms 576
Central globe 18
Atomic weight 64.91
Number weight 1170/18 65.00
CADMIUM (Plate IX, 3) has an increased complexity of funnels; the diagram
shows one of the three similar segments which lie within the funnels as
cylinders; each of these contains four spheres, three pillars and three
ovoids, like the spike of zinc turned upside down, and the zinc ten-atomed
triangle changed into three ten-atomed ovoids. The centre-piece is a new
form, though prefigured in the central globe of zinc.
CADMIUM: 3 segments of 164 atoms = 492
4 funnels of 492 atoms 1968
Central body 48
Atomic weight 111.60
Number weight 2016/18 112.00
The corresponding negative group is headed by
[Illustration: PLATE X.]
SULPHUR (Plate X, 1), which, like magnesium, has no central globe, and consists simply of the zinc funnels, much less compressed than zinc but the same in composition.
SULPHUR: 4 funnels of 144 atoms
Atomic weight 31.82
Number weight 576/18 32.00
SELENIUM (Plate X, 2) is distinguished by the exquisite peculiarity, already noticed, of a quivering star, floating across the mouth of each funnel, and dancing violently when a ray of light falls upon it. It is known that the conductivity of selenium varies with the intensity of the light falling upon it, and it may be that the star is in some way connected with its conductivity. It will be seen that the star is a very complicated body, and in each of its six points the two five-atomed spheres revolve round the seven-atomed cone. The bodies in the funnels resemble those in magnesium, but a reversed image of the top one is interposed between itself and the small duad, and each pair has its own enclosure. The central globe is the same as that of zinc.